Over a five-year period 100 cadaveric renal transplants were performed. In 91 of these recipients, a prophylactic parenteral antibiotic (cefoperazone) was administered and closed wound drainage was used. Of these 91 patients, 33 received azathioprine/prednisone immunosuppression, whereas cyclosporine/prednisone with or without azathioprine was used in the remaining 58. The incidence of wound infections was significantly reduced from 12 per cent (4/33) in the azathioprine group to 1.7 per cent (1/58) in the cyclosporine group (p less than 0.01). When conventional immunosuppression (azathioprine/prednisone) is employed in renal transplantation, triple antibiotic prophylaxis that includes an aminoglycoside is most effective in preventing wound infections. A single non-nephrotoxic antibiotic, cefoperazone, offers similar protection in the cyclosporine/prednisone-treated renal transplant recipient.